Islamic State Video Shows Beheading of U.S. Journalist Steven Sotloff

White House Says Intelligence Community Confirms That Video of Killing Is Authentic

A disguised militant from the Islamic State, or ISIS, said the execution of an American journalist purportedly shown in a new video was the result of U.S. airstrikes in Iraq. This clip features an audio excerpt from the militant's video speech.

BAGHDAD—The White House said Wednesday the video showing the killing of U.S. journalist Steven Sotloff is authentic.

The extremist group Islamic State posted a video on Tuesday purporting to show the beheading of the American journalist, bringing calls for the U.S. to more forcefully confront the militants in both Iraq and Syria.

"The U.S. intelligence community has analyzed the recently released video showing U.S....